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Session 37 - First Results from the Solar and Heliospheric Observatory (SOHO).
Display session, Tuesday, June 11
Tripp Commons,

[37.13] A Solar EUV Spectral Atlas Observed with SUMER

P. Brekke (Univ. of Oslo), K. Wilhelm (MPAE, Lindau), P. Lemaire (IAS, Orsay), W. Curdt, U. Schühle (MPAE, Lindau), A. Poland, T. Kucera (NASA/GSFC), D. M. Hassler (HAO/NCAR), O. H. W. Siegmund (UC, SSL, Berkeley)

We present the first solar EUV spectral atlas in the wavelength range 500 -- 1600 ÅThe spectra were recorded with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) which is part of the ESA/NASA Solar and Heliospheric Observatory (SOHO). The solar spectrum below 1200 Åis not very well known. Thus, the present spectral atlas, and SUMER observations in general, represents a new important diagnostic tool to study essential physical parameters of the solar atmosphere. It includes emission from atoms and ions in the temperature range 10^4 to 2 \times 10^6 K. Thus, emission lines and continua emitted from the lower chromosphere to the lower corona can be studied. The atlas is also useful as a planning tool for SUMER studies to determine useful dwell times, possible blends, and to select proper data extraction windows.

The angular resolution of SUMER is close to 1 arcsec, but the atlas presented here represents an average along part of the 1-arcsec wide slit, typically 30 arcsec. The spectral resolving power of the instrument is \lambda/\Delta \lambda = 17770-38300. For more details about the SUMER instrument we refer to Wilhelm et al. (Solar Physics, 162, 189, 1995).

The spectral data in this atlas were obtained with the spectrometer slit positioned at the center of the solar disk with a dwell time of 300 s to bring up weak lines and continua. The full spectral range was put together from a number of exposures each covering approximately 20 Åin 1st order on the coated, and therefore most sensitive, part (KrB) of the detector. 1st and 2nd order spectra are superimposed. The spectral atlas is available in a computer readable format together with a IDL program to read and display the data using a widget interface. The atlas and the programs can be obtained via the World Wide Web ( or by contacting one of the authors.

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